Problems with corrosion in reactors
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I have a jacketed reactor made of Q345R material, with a corrosion margin of 4. The original wall thickness was 18 mm; we measure the wall thickness once a year. It was put into use in 2017, and this year the measured wall thickness is around 14.50 mm. I would like to know at what thickness the reactor should no longer be used
Without the corresponding design parameters, it is impossible to answer.
There are calculation sheets in the equipment file; check the calculation sheets! Additionally, whether it can be used also depends on the recommendations of regulatory authorities!
Check the calculated thickness in the calculation sheet; it cannot be used if it is lower than that value. Whether it can actually be used depends on the test reports issued by authoritative professional institutions
Pressure vessels are inspected annually by regulatory authorities; we must heed their recommendations.
Make an estimate without looking at the strength calculation sheet. Corrosion rate (18-14.5)/4 years = 0.875 mm/year. This is severe corrosion. What medium is inside? Based on the parameters, assuming the design life of this device is 10 years, it should corrode by 4 mm within those 10 years. But in reality, after just 4 years, it reaches 3.5 mm, which means it reaches the end of its useful life after 4.5 years.
According to the TSG21-2016 Regulations for the Inspection of Fixed Pressure Vessels, when the thickness reduction of a vessel exceeds its corrosion allowance, a strength check must be conducted. If the strength check passes, the vessel can continue to be used; otherwise, it cannot be used. Although the thickness reduction of this vessel does not exceed 4 mm, a strength check can still be carried out based on the design parameters to determine whether it can be used in the next maintenance cycle
Check the conclusions of the regular inspection report for pressure vessels.
Without operating conditions, how can it be determined? Then, let’s use it until it’s completely worn out.